This grant is the biological part of a collaborative study of the psychobiology of depression. There is a biological part and a separately numbered and funded clinical part. The biological part obtains information on patients with primary affective disorder, other psychiatrically ill patients, and normal comparison groups (inpatient and outpatient). The chemical constituents measured include plasma levels of tricyclic antidepressants and MHPG, spinal fluid levels of HVA, HIAA and MHPG. There will also be an insulin tolerance test and a dexamethasone suppression test to test the hypothalamic pituitary axis. The intention is to have approximately 16 subjects and 4 inpatient comparison individuals so that there will be a large enough sample from which to make inferences concerning the meanings of the biological results found.